This invention relates in general to preventing the production of particulate materials through a wellbore traversing an unconsolidated or loosely consolidated subterranean formation and, in particular, to an apparatus and method for progressively gravel packing an interval of the wellbore.
It is well known in the subterranean well drilling and completion art that relatively fine particulate materials may be produced during the production of hydrocarbons from a well that traverses an unconsolidated or loosely consolidated formation. Numerous problems may occur as a result of the production of such particulates. For example, the particulates cause abrasive wear to components within the well, such as tubing, pumps and valves. In addition, the particulates may partially or fully clog the well creating the need for an expensive workover. Also, if the particulate matter is produced to the surface, it must be removed from the hydrocarbon fluids using surface processing equipment.
One method for preventing the production of such particulate material to the surface is gravel packing the well adjacent to the unconsolidated or loosely consolidated production interval. In a typical gravel pack completion, a sand control screen is lowered into the wellbore on a workstring to a position proximate the desired production interval. A fluid slurry including a liquid carrier and a relatively coarse particulate material, which is typically sized and graded and which is referred to herein as gravel, is then pumped down the workstring and into the well annulus formed between the sand control screen and the perforated well casing or open hole production zone.
The liquid carrier either flows into the formation or returns to the surface by flowing through a wash pipe or both. In either case, the gravel is deposited around the sand control screen to form the gravel pack, which is highly permeable to the flow of hydrocarbon fluids but blocks the flow of the fine particulate materials carried in the hydrocarbon fluids. As such, gravel packs can successfully prevent the problems associated with the production of these particulate materials from the formation.
It has also been found, however, that it is difficult to completely gravel pack the production interval. This is particularly true in long or inclined/horizontal production intervals. The resulting incomplete gravel packs are commonly caused by entry of the liquid carrier into permeable sections of the production interval creating sand bridge formation in the annulus. Thereafter, the sand bridge prevents the gravel pack slurry from flowing to the remainder of the annulus which, in turn, prevents the placement of sufficient gravel in the remainder of the annulus.
Therefore a need has arisen for an apparatus and method that is capable of producing a substantially complete gravel pack of the wellbore adjacent to the production interval to prevent the production of fine particulate materials when production from the formation commences.
The present invention disclosed herein comprises an apparatus and method that is capable of producing a substantially complete gravel pack of the wellbore adjacent to the production interval to prevent the production of fine particulate materials when production commences. The apparatus and method of the present invention achieves this result by progressively gravel packing the production interval from one end to the other.
The apparatus comprises a sand control screen that is positioned within the wellbore and a tubular member also positioned within the wellbore forming a first annulus with the sand control screen and a second annulus with the wellbore. The tubular member initially substantially prevents fluid communication between the first annulus and the second annulus. Thereafter, the tubular member selectively allows fluid communication from the first annulus to the second annulus by progressively establishing fluid communication between the first annulus and the second annulus from a first end to a second end of the interval.
The tubular member may include a perforated pipe having a plurality of removable members positioned on the interior or the exterior of the perforated pipe. The removable members may alternatively be positioned within the wellbore without being associated with a perforated pipe. In either case, the removable members may be propellant or other combustible material members each having an initiator. The initiators may be activated by a wireless telemetry system. Alternatively, the initiators may have pressure activated firing devices that are positioned such that the pressure required to fire the pressure activated firing devices progressively increasing from the first end to the second end interval.
The removable members may alternatively be friable members that are progressively removable from the first end to the second end of the interval. Each friable member may include a pressure actuated vibration generator. In this case, the pressure actuated vibration generators are positioned within the wellbore such that the pressure required to activate the pressure actuated vibration generators progressively increasing from the first end to the second end of the interval. Alternatively, each of the friable members may have a vibration generator that activated by a wireless telemetry system.
The tubular member may alternatively comprises a perforated pipe having an actuatable device disposed within each perforation. The actuatable devices may be rupture disks, pressure actuated one-way valves or other pressure actuated devices that are positioned within the perforated pipe such that the pressure required to actuate the actuatable devices progressively increases from the first end to the second end of the interval. Alternatively, the actuatable device may be progressively actuated from the first end to the second end of the interval by a wireless telemetry system.
In all embodiments, the gravel pack may progress from the top of the interval to the bottom, the bottom of the interval to the top, the heel of the interval to the toe or the toe of the interval to the heel.
The method of the present invention comprises traversing a formation with the wellbore, locating a sand control screen within the wellbore proximate the formation, positioning a tubular member within the wellbore that forms a first annulus between the tubular member and the sand control screen and a second annulus between the tubular member and the wellbore, initially substantially preventing fluid communication between the first annulus and the second annulus, injecting a fluid slurry containing gravel into the first annulus, progressively establishing fluid communication between the first annulus and the second annulus from a first end to a second end of the interval and terminating the injecting when the interval is substantially completely packed with the gravel.